adjective. 
                    Pertaining to, or near, the horizon.
                  
                
                  
                    adjective. 
                    Parallel to the horizon; on a level.
                  
                
                  
                    adjective. 
                    Measured or contained in a plane of the horizon.
                  
                
                  
                    adjective. 
                    a drilling machine having a horizontal drill spindle.
                  
                
                  
                    adjective. 
                    one the piston of which works horizontally.
                  
                
                  
                    adjective. 
                    the fire of ordnance and small arms at point-blank range or at low angles of elevation.
                  
                
                  
                    adjective. 
                    the horizontal component of the earth's magnetic force.
                  
                
                  
                    adjective. 
                    a constructive line, either drawn or imagined, which passes through the point of sight, and is the chief line in the projection upon which all verticals are fixed, and upon which all vanishing points are found.
                  
                
                  
                    adjective. 
                    See under Parallax.
                  
                
                  
                    adjective. 
                    a plane parallel to the horizon, upon which it is assumed that objects are projected. See Projection. It is upon the horizontal plane that the ground plan of the buildings is supposed to be drawn.
                  
                
                  
                    adjective. 
                    a projection made on a plane parallel to the horizon.
                  
                
                  
                    adjective. 
                    the distance in a horizontal plane to which a gun will throw a projectile.
                  
                
                  
                    adjective. 
                    a water wheel in which the axis is vertical, the buckets or floats revolving in a horizontal plane, as in most turbines.